Eighteen demonstrators were arrested Saturday in St. Paul, Minnesota, after they blocked one of the city’s freeways to protest the police shooting death of a black man.

The arrests came after a jury acquitted a police officer Jeronimo Yanez in the fatal shooting of Philando Castile during a traffic stop last year — a verdict that brought cries of dismay from the dead man’s family and supporters in the courtroom.

The protesters had been engaged in a peaceful demonstration Friday outside the Minnesota State Capitol, before a group of about 1,500 of them decided to stand in the middle of Interstate 94, blocking traffic on the freeway, police said.

In a statement, a Minnesota State Patrol spokeswoman said the protesters were charged with unlawful assembly, among other things, after they declined repeated demands from police to vacate the roadway.

Yanez dismissed after trial

The small city (Saint Anthony Village, Minnesota) that employed Yanez as a policeman dismissed him immediately after he was found not guilty of second-degree manslaughter. The 29-year-old officer has not been on active duty since the shooting last July.

“The public will be best served if Officer Yanez is no longer a police officer in our city,” a statement on the city’s website said.

Thousands of chanting demonstrators marched through the streets of St. Paul, the capital, Friday evening, to protest the officer’s acquittal. Many held signs that read “Black Lives Matter” and “Blue Lies Matter” as they headed for the St. Paul Cathedral. Some chanted “Hands Up, Don’t Shoot.”

Mayor appeals for calm

The city’s mayor, Chris Coleman, ordered community centers to remain open for public discussions, and appealed for calm. “As people across our city, county and country react to the jury’s verdict, I urge each of us to move forward in a way that is peaceful and respectful of everyone — residents, demonstrators and police officers alike,” he said.

Much of the incident, in which Castile, 32, was shot in his car, was streamed live on social media. Castile’s girlfriend, sitting beside him as Yanez fired seven shots, said she recorded video of the scene because she feared that she and her 4-year-old daughter, in the car’s rear seat, were in danger.

The girlfriend, Diamond Reynolds, said on the video and testified in court that Castile had been reaching for his driver’s license to comply with the policeman’s order.

Yanez said he acted because he feared for his life and believed Castile was reaching for a gun. The dead man had told the policeman he had a gun elsewhere in the car. The last words he spoke before expiring were, “I wasn’t reaching for it.”

Questioned by his defense attorney during the trial, Yanez said: “I was scared to death. I thought I was going to die. I had no other choice.”

Dashboard camera

Prosecutors in St. Paul, Minnesota, said recordings from the car — both from Reynolds’ phone and from a dashboard camera — showed that Castile was courteous and non-threatening, and they told the court there was no justification for Yanez’ action.

Moans of dismay and weeping swept through the courtroom after the verdict was announced. Court officers hustled Yanez and the jurors out of the room.

The dead man’s mother, Valerie Castile, speaking to reporters outside the court afterwards, said: “I’m mad as hell right now. Yes, I am. My first-born son died. … Just because he (Yanez) was a police officer that makes it OK.”

Weeks of protests

Yanez, who is Latino, testified he stopped Castile in a suburb of St. Paul, Falcon Heights, because he thought Castile resembled someone who robbed a nearby store several days earlier. Castile’s family said he was profiled because of his race, African-American.

Circumstances of the shooting led to weeks of protests last year in St. Paul and the adjoining city of Minneapolis, and fueled a national debate about the appropriate use of force by police against racial minorities.